Overheating or over-using the frying oil leads to formation of rancid-tasting products of oxidation, polymerization, and other deleterious, unintended or even toxic compounds such as acrylamide (from starchy foods). Deep-frying under vacuum helps to significantly reduce acrylamide formation, but this process is not widely used in the food industry due to the high investment cost involved.

Some useful tests and indicators of excessive oil deterioration are the following:

Instruments that indicate total polar compounds, currently the best single gauge of how deep-fried an object is, are available with sufficient accuracy for restaurant and industry use.

Deep frying produces large amounts of waste oil, which must be properly disposed. Waste oil is increasingly being recycled into biodiesel.

Some deep fry shortenings contain trans fat.

Cooking oil is flammable, and fires may be caused by it igniting at too high a temperature. Attempts to extinguish an oil fire with water cause the water to flash into steam due to the high heat of the oil, in turn sending the burning oil in all directions and thus aggravating the fire. Instead, oil fires must be extinguished via fire extinguisher or by smothering. Other means of extinguishing an oil fire include application of dry powder (e.g., baking soda, salt) or fire fighting foam. Most commercial deep fryers are equipped with automatic fire suppression systems using foam.

The iPhone allows audio conferencing, call holding, call merging, caller ID, and integration with other cellular network features and iPhone functions. For example, if music is playing when a call is received, the music fades out, and fades back in when the call has ended.

The proximity sensor shuts off the screen and touch-sensitive circuitry when the iPhone is brought close to the face, both to save battery and prevent unintentional touches. The iPhone does not support video calling or videoconferencing on versions prior to the fourth generation, as there is only one camera on the opposite side of the screen.

The iPhone 4 supports video calling using either the front or back camera over Wi-Fi, a feature Apple calls Face Time. The first two models only support voice dialing through third-party applications. Voice control, available only on the iPhone 3GS and iPhone 4, allows users to say a contact’s name or number and the iPhone will dial.

The iPhone includes a visual voicemail (in some countries) feature allowing users to view a list of current voicemail messages on-screen without having to call into their voicemail. Unlike most other systems, messages can be listened to and deleted in a non-chronological order by choosing any message from an on-screen list.

A music ringtone feature was introduced in the United States on September 5, 2007. Users can create custom ringtones from songs purchased from the iTunes Store for a small additional fee. The ringtones can be 3 to 30 seconds long from any part of a song, can fade in and out, pause from half a second to five seconds when looped, or loop continuously. All customizing can be done in iTunes, or alternatively with Apple’s Garage Band software 4.1.1 or later (available only on Mac OS X) or third-party tools.

A hip flask is a thin flask for holding adistilled beverage; its size and shape are suited to a trouser pocket. Hip flasks were traditionally made of pewter,silver, or even glass, though most modern flasks are made from stainless steel. Some modern flasks are made of plastic as to avoid detection by metal detectors. Hip flasks can vary in shape, although they are usually contoured to match the curve of the wearer’s hip or thigh, for comfort and discretion. Some flasks have “captive tops” which is a small arm which attaches the top to the flask to stop it getting lost when it’s taken off. A hip flask is most commonly purchased, and then filled by the owner. However, the term “flask” also applies to smallest bottle sizes of alcohol in commercial markets. Some flasks come with small cups to make sharing easier, although generally liquid is drunk directly from the flask. The hip flask is popular as commemorative item, often being engraved. The Modern Drunkard Magazine describes the engraved flask as the best present one can give. The engravings may be a short quote, the recipient’s initials, toasts, dates of memorable occasions, or signs of friendship.